Programmable logic controllers are an important part of contemporary industrial automation systems. Growing system complexity and increasing quality expectations, however, are increasing the demand for more efficient testing processes. System vendors' aim to cut the development costs and speed up the delivery process set a limit to the number of test engineers and time available for testing. Test automation systems have established their role in software testing domain but limitations and challenges encountered when testing physical devices have kept such methods out of the reach of industrial automation testers.
This thesis studies the feasibility of OPC Unified Architecture as a platform independent communication protocol between a test automation framework and programmable logic controllers. The work presents an architectural design for a test automation framework suitable for testing OPC UA -enabled programmable logic controllers. The design is based on requirements drawn from research towards industrial automation testing processes and best practices in test automation. The design is evaluated by creating an implementation of the system and using it to conduct a series of automated I/O -tests for the test platform.
The results suggest that the platform independent nature of OPC Unified Architecture fares well when aiming for vendor independent interconnectivity between a general test automation framework and a programmable logic controller. Furthermore, by using test automation methods familiar from software test domain, it is possible to streamline the testing processes of physical devices to some extent even if not all testing activities can be automated.